PARK CITY — The flip side of Richard Rowley's Dirty Wars, which registers horror at the vast sprawl of U.S. secret military activity, Greg Barker's Manhunt is a fascinated account of one instance where all that shadowy work eventually achieved the desired effect. Acknowledging serious moral questions but setting them outside its purview, the thoroughly involving doc sheds light on how information was pieced together while leaving debates over the techniques that gathered it for viewers to conduct. Interest should be strong for its May HBO airdate.

Where Zero Dark Thirty introduced audiences to the important role female agents played in this campaign, Manhunt goes further, making it clear just how woman-driven the early analysis of bin Laden's activities was. We meet what the film calls "The Sisterhood," analysts whose careful study of Middle East intel caused them to focus on him almost a decade before 9/11. The women both defy stereotype and embrace the different ways men and women think: Cindy Storer, seen teary-eyed here more than once, suggests that a woman's tears are a lot less unproductive to an investigation than having an angry man throw things around.

We hear just how many reports these women filed with messages as urgent as the now-famous “Bin Laden Determined to Strike the United States." Manhunt doesn't quite explain how those memos failed to produce a response before 9/11, beyond CIA director John McLaughlin's sad assertion that the reports contained "nothing actionable."

We meet more expected characters as well, like the colorful Marty Martin, an Arabic speaker from Louisiana who can't tell a story without throwing his upper body into it. His brand of macho is balanced by that of Jose Rodriguez, a more businesslike CIA case officer, who was involved in coercive interrogations. The two men represent the "we did what it took" position, Rodriguez boasting that "you can't argue with success."

A more nuanced view comes from Nada Bakos, a targeter who pursued the leader of al-Qaeda in Iraq and helped focus attention on the group's courier network. Bakos acknowledges that each person in the manhunt had to define his or her own moral center. Discussing the problem of integrating thousands of individual moral centers into a coherent government-wide rulebook is left to another film.

Very sharp graphics by The Mill help Barker convey the sense of an endless whiteboard, where headshots are identified, surrounded by bits of known data, and connected to other terrorists in an increasingly complex flow chart. We all know this mission's most visible goal was achieved. But in explaining how that happened, Manhunt can't help but illustrate the near-hopelessness of declaring war on not an individual or nation but on a technique, terror, so readily adopted by enemies around the world.